DL380 G6 power supply light and shutdown

We have a client with a DL380 G6 that has been shutting down unexpectedly. When it shuts down both power supply lights on the status display show orange, the power supply button is red and the status light blinks red.

They will restart the system and the PS1 light on the display goes out, and PS2 light will blink green. The power supplies' LEDs are both green. We've replaced power supply 2 and the power distribution board. I don't know if the system has shut down since then, but PS2 still blinks green on the panel.